Stabilization of n-chloro-imides

ABSTRACT

CLEANSING COMPOSITIONS CONTAINING AN N-CHLORO-IMIDE AND A STABILIZING AMOUNT OF A MERCAPTAN COMPOUND OF THE FOLLOWING STRUCTURAL FORMULA:   WHEREIN R IS SELECTED FROM THE GROUP CONSISTING OF ALKYL CONTAINING FROM 4-12 CARBON ATOMS, PHENYL AND BENZYL.   R-SH

United States Patent 3,578,598 STABILIZATION 0F N-CHLORO-IMIDES Richard L. Burke, Madison, N.J., assignor to Colgate- Palmolive Company, New York, N-Y. N0 Drawing. Filed May 29, 1968, Ser. No. 732,844 Int. Cl. Clld 7/54 US. Cl. 252-102 12 Claims ABSTRACT OF THE DISCLOSURE Cleansing compositions containing an N-chloro-imide and a stabilizing amount of a mercaptan compound of the following structural formula:

wherein R is selected from the group consisting of alkyl containing from 4-12 carbon atoms, phenyl and benzyl.

The present invention relates in general to the stabilization of compositions adapted to perform in use primarily an oxidizing function and, in particualr, to the provision of improved stabilizing agents for such purposes.

The utilization of bleaching agents of the hypochloriteliberating type in the formulation of compositions adapted to perform an oxidizing function, e.g., bleaching and detergent compositions, scouring cleansers, etc., is well known in the art being extensively described in the published literature both patent and otherwise. Hypochlorite type bleaching agents, i.e., those bleaching agents which on contact with aqueous media are capable of liberating hypochlorite comprise a relatively preferred class of oxidizing agents in view of the comparatively high bleaching levels, i.e., oxidization rates, obtainable therewith. Particularly beneficial results as regards bleaching activity are purportedly obtained with bleaching agents of the N- chloro-imide type. The latter materials, although possessed of a relatively high order of oxidizing efiiciency nevertheless prove somewhat objectionable in view of the manifold problems encountered in connection with attempts to stabilize such compounds against loss of chlorine. As is well known, trichlorocyanuric acid, a powerful oxidizing agent, possesses three labile positive chlorine atoms held only by a nitrogen-chlorine or oxygenchlorine bond.

In view of the relatively high reactivity characterizing the chlorine atom present in the trichlorocyanuric acid material as well as the comparatively weak bond of attachment to the trichlorocyanuric acid molecule, there exists a pronounced tendency for reaction with other composition ingredients or with other trichlorocyanuric acid molecules resulting in self decomposition. As will be readily recognized, occurrence of such phenomena to any substantial extent tends to vitiate any possibility of obtaining the favorable bleaching properties normally characterizing such compounds.

In an effort to overcome or otherwise mitigate the foregoing and related problems, considerable industrial activity has centered around the research and development of means whereby to render bleaching agents of the N- chloro-imide type adequately stable against chlorine loss. Although much in the way of meritorious achievement has been accomplished, many of the stabilizing agents thus far promulgated in the art for such purposes are found to be subject to one or more serious disadvantages. As examples of problems frequently encountered in connection with the use of stabilizing agents of the type heretofore provided, there may be mentioned, for example,

ice

the failure of such compounds to impart to the oxidizing or bleaching composition the desired level of stabilization for periods of time consonant with efficacious and convenient use. Thus, it is found that the stabilizing capacity of a given compound diminishes rather markedly over relatively short periods of standing, e.g., in periods of time ranging from approximately one to two days under relatively mild conditions of temperature, humidity, etc. Moreover, many of the stabilizer compounds heretofore recommended present serious problems as regards facility of incorporation into the oxidizing composition. Thus, many of such materials may be handled only with extreme difficulty; in addition, in many cases, it becomes necessary to resort to the use of additional ingredients for purposes of promoting or otherwise augmenting compatibility of the stabilizer compound in the particular oxidizing composition relationship. As will be recognized, any one of the aforementioned factors may be of such import as to militate against the propriety of using a given stabilizer compound which might otherwise recommend itself.

In accordance with the discovery forming the basis of the present invention, it has been ascertained that a rather specific and delimited class of compounds exhibits synergistic stabilizing action When incorporated into oxidizing compositions containing therein one or more bleaching agents of the N-chloro-imide type.

Thus, a primary object of the present invention resides in the provision of stabilizing agents advantageously adapted for use in connection with oxidizing compositions containing at least one N-chloro-imide bleaching agent wherein the foregoing and related disadvantages are eliminated or at least mitigated to a substantial extent.

Another object of the present invention resides in the provision of stabilizer compounds for bleaching compositions containing one or more N-chloro-imide bleaching agents, said stabilizer compound being capable of effectively stabilizing said N-chloro-imide compound against loss of chlorine.

A further object of the present invention resides in the provision of stabilizer compounds for oxidizing compositions containing at least one N-chloro-imide bleaching agent, said stabilizer being capable of effectively reducing chlorine loss for relatively extended periods of time.

Other objects and advantages of the present invention will become more apparent hereinafter as the description proceeds.

The attainment of the foregoing and related objects is made possible in accordance with the present invention which in its broader aspects includes the provision of compositions adapted to perform an oxidizing function, said compositions containing at least one N-chloro-imide bleaching agent and a stabilizer compound comprising a mercaptan compound of the following structural formula:

wherein R represents alkyl containing from 4 to 12 carbon atoms, phenyl and benzyl. Suitable alkyl substituents include, for example, butyl, isobutyl, pentyl, hexyl, octyl, dodecyl, etc.

The mercaptan compounds encompassed by the above depicted structural formula are uniformly characterized in exhibiting a pronounced capability to stabilize oxidizing compositions containing an N-chloro-imide bleaching agent for extended periods of time despite subjection to extreme temperature conditions. Thus, and as will be made manifestly clear in the examples which follow,

bleaching compositions containing the mercaptan stabilizer exhibit minimal, if not negligible, loss of chlorine upon standing for significant periods of time despite environmental temperatures approximating 140 F. By way of coantrast, similar compositions, but devoid of the mercaptan stabilizer, exhibited an intolerable level of chlorine loss to the extent that such compositions proved highly inefficient for even mild cleansing applications.

A further advantage characterizing the mercaptan compounds described herein relates to the exceptionally high degree of stabilization against chlorine loss obtainable therewith despite their use in minimal concentrations. In this connection, it is found that concentrations of mercaptan stabilizer on the order of only about 0.001 to about 0.1% by weight of bleach composition sufiice to substantially eliminate any possibility of significant chlorine loss. Optimum concentrations will vary somewhat depending upon, of course, the particular use contemplated for the composition being formulated. Thus, for example, in the case of fabric bleaching and washing operations, wherein the concentration of hypochloriteliberating compound may fall within the lower ranges, the required concentration of mercaptan compound is correspondingly reduced. In other applications wherein the soil-removal problem may be somewhat more severe, e.g., as would be the case with scouring cleanser compositions, the concentration of mercaptan employed would increase with increased quantities of N-chloro-imide compound. In any event, it is found that beneficial results for the vast majority of cleansing applications may be obtained by the use of the mercaptan compound in amounts suflicient to yield a mole ratio of mercaptan to N-chloro-imide bleaching agent within the range of from about 1/1 to about 1/20 with a range of U2 to l/lO being particularly preferred.

The N-chloro-imide bleaching agents contemplated for use in accordance with the present invention are preferably provided in particulate form in a substantially dry state, i.e., devoid of free water; the terminology devoid of free water should not, however, be interpreted as excluding the presence of water of crystallization or hydration. In general, it is found that optimum realization of the improvements described herein attend those procedures wherein the N-chloro-imide compound is employed within certain particle size limitations; preferably the major portion of the N-chloro-imide compound (60 to 90%) should be that which passes through a 200 mesh screen. As specific examples of N-chloro-imide compounds found to be particularly suitable in the practice of the present invention, there may be mentioned without necesi sary limitation trichloroisocyanuric acid (TCCA), dichloroisocyanuric acid (DCCA). sodium dichloroisocyanurate, potassium dichloroisocyanurate, etc.

The N-chloro-imide compound may be employed in concentrations varying over a relatively wide range, the

specific concentration selected being dictated in large part by the severity of the cleaning problem likely to be encountered by the composition being formulated. In any event, it is found that satisfactory negotiation of the broad spectrum of cleaning problems likely to be confronted can be attained by the use of the N-chloro-imide compound in amounts sufiicient to yield a concentration within the range of 0.1 percent to 90 percent and higher and preferably from 10 percent to 90 percent and higher by weight of composition of laundry bleaching detergents and 0.1 percent to 5 percent by weight of composition of cleansers.

The mercaptan compound in combination with the N- chloro-imide bleaching agent comprise the critical components of the compositions herein described. The exceptional stability of compositions prepared with same against decomposition on aging under relatively severe conditions of storage, i.e., conditions which would otherwise in the normal course of events give rise to inordinately high levels of N-chloro-imide decomposition and corresponding loss of chlorine is highly advantageous from a further standpoint. The decomposition products of many N-chloro-imide bleaching agents are highly corrosive; thus, considerable care must necessarily be exercised as regards storage of compositions which tend to evolve same. The instant compositions tend to eliminate problems associated with corrosion of metallic containers in view of the significant reduction in chlorine loss. Moreover, the corresponding reduction in risk of handling is of paramount importance in connection with personal safety.

The N-chloro-imide compounds stabilized in accordance with the present invention may be employed in any substantially dry composition in which the N-chloroimide compound is otherwise suitable for use, such as washing, bleaching, sterilizing and disinfecting compositions. Thus, the N-chloro-imide bleaching agent/mercaptan stabilizer systems may be utilized in admixture with detergent or surface active materials which exhibit substantial stability in the presence of the N-chloro-irnide bleaching agent. Detergent materials contemplated for use in accordance with the present invention encompass a relatively wide range of materials. The particular material selected may be of the soap or soapless variety. The latter materials may be designated as water-soluble salts of organic reaction products having in their molecular structure an anionic solubilizing group such as SO H, SO H, COOH and PO H and an alkyl or aralkyl radical having about 8 to 22 carbon atoms in the alkyl group. Suitable detergents are anionic detergent salts having alkyl substituents of 8 to 22 carbon atoms, such as: Watersoluble sulfated and sulfonated anionic alkali metal and alkaline earth metal detergent salts containing a hydrophobic higher alkyl moiety, such as salts of higher alkylmono or polynuclear aryl sulfonates having from about 8 to 18 carbon atoms in the alkyl group which may have a straight or branched structure, e.g., sodium dodecylbenzene sulfonate, magnesium tridecylbenzene sulfonate, lithium or potassium pentapropylene benzene sulfonate; alkali metal salts of sulfated condensation products of ethylene oxide (e.g., 3 to 20 and preferably 3-10 mols of ethylene oxide per mol of other compound) with aliphatic alcohols containing 8 to 18 carbon atoms, or with alkyl phenols having alkyl groups containing 6 to 18 carbon atoms, e.g., sodium nonyl phenol pentaethoxamer sulfate and sodium lauryl alcohols containing from about 8 to 18 carbon atoms, e.g., sodium lauryl sulfate and sodium stearyl sulfate; alkali metal salts of higher fatty acid esters of low molecular weight alkylol sulfonic acid, e.g., fatty acid esters of the sodium salt of isothionic acid; fatty ethanolamide sulfates; fatty acid amides of amino alkyl sulfonic acids, e.g., lauric acid amide of taurine; alkali metal salts of hydroxy alkane sulfonic acids having 8 to 18 carbon atoms in the alkyl group, e.g., hexadecyl alphahydroxy sodium sulfonate. Particularly preferred for use herein are the olefin sulfonates. In general these organic surface active agents are employed in the form of their alkali metal salts or alkaline earth metal salts because such salts possess the requisite stability, water solubility. and low cost essential to practical utility.

Suitable water-soluble, higher fatty acid salts which are used in conjunction with the foregoing anionic detergents include alkali metal salts of saturated, unsaturated, or mixtures of unsaturated and saturated, fatty acids containing from about 8 to about 18 carbon atoms in the molecule such as: sodium caprate, sodium laurate, sodium myristate, sodium palmitate, potassium oleate, sodium stearate, sodium and potassium salts of tallow fatty acids, sodium and potassium salts of coconut oil fatty acids, and the like.

Generally, a water-soluble higher fatty acid salt will be added to compositions of the invention as a salt. However, a water-soluble higher fatty acid salt can also be formed in situ by adding stoichiometric amounts of the desired fatty acid and the desired alkaline hydroxide directly to a composition; or alternatively, by adding a desired fatty acid or fatty acid mixture directly to a heavyduty detergent composition where the normal alkalinity desirable in such compositions is sufiicient to form the water-soluble, higher fatty acid salt.

It is essential, of course, that the stabilized N-chloroimide bleach material be maintained in substantially dry condition. Accordingly, it is recommended that such compositions be packaged in moisture impermeable containers such as containers fabricated from glass, metal, metal foil, metal foil-covered paper border, etc. The latter material proves particularly effective in view of its light weight and resilient character.

The compositions of the present invention are preferably provided in particular form, the particles having an average particle size of less than about mesh. Within this range optimum particle size depends for the most part upon the use contemplated for the product formulated. For example, in the case of abrasive cleansers, the particle size is preferably less than about 200 mesh. In contradistinction, in the preparation of spray-dried compositions, the recommended particle size is such that substantially the entire product passes through a 10 mesh sieve being retained on a 100 mesh sieve.

The nature of the auxiliary ingredients include in the basic composition, i.e., the mercaptan stabilizer and N- chloro bleaching agent depends to a great extent upon the ultimate use contemplated for such compositions. Typically, a substantially dry abrasive cleanser prepared in accordance with the present invention would comprise the N-chloro-imide compound, the mercaptan stabilizer, and a major proportion of finely divided, water insoluble siliceous abrasive such as silica, feldspar, pumice, volcanic ash, diatomaceous earth, bentonite, talc, etc., as well as mixtures of two or more of the foregoing materials.

In the preparation of water soluble bleaching and detergent compositions, it is found that particularly beneficial results are obtained with the employment of the detergent compound in amounts ranging up to about 60% i.e., from 0-60% and preferably from about to about 40% by weight of the composition. Any of the conventional adjuvants customarily employed in the preparation of bleaching and detergent compositions may likewise be included such as fluorescent brighteners, water soluble inorganic and organic builder salts, the latter being employed in amounts ranging up to about 95% with a range of from about 50 to about 95% by weight of the composition being preferred. Suitable builders include, for example,

Trisodium phosphate,

Tetrasodium pyrophosphate,

Sodium acid pyrophosphate,

Sodium tripolyphosphate,

Sodium monobasic phosphate,

Sodium dibasic phosphate,

Sodium hexamethaphosphate,

Sodium silicates, SiO /Na O of 1/1 to 3.2/1 Sodium carbonate,

Sodium sulfate,

Borax,

Nitriloacetic acid trisodium salt,

Ethylene diamine tetraacetic acid tetrasodium salts, etc.

Mixtures of two or more inorganic or organic salts can be used, as can mixtures of inorganic and organic salts.

Particularly preferred herein are water-soluble, alkali metal polyphosphate builder salts. These salts form watersoluble complexes with calcium and magnesium ions found in hard water and thereby prevent the formation of insoluble salts which tend to deposit upon textiles during a washing cycle. Further, such phosphates enhance the detersive efiiciency of anionic detergents, aid in controlling sudsing and powers and aid in keeping soil suspended in the washing bath after its removal from the soiled textiles.

Various other materials may be included in compositions of the invention. Examples thereof are the higher fatty acid amides such as coconut or lauric monoethanolamide, isopropanolamide and the like; hydrotropic solubilizing agents such as xylene or toluene sulfornates; organic solubilizing agents such as ethanol, ethylene glycol and hexylene glycol; sodium carboxymethylcellulose and polyvinyl alcohol antiredeposition agents; optical and fluorescent brightener materials; coloring agents; corrosion inhibiting agents; germicides; perfumes, bluing agents; and the like.

Preferred compositions advantageously contain a hydrophobic colloidal cellulosic soil-suspending agent which is soluble or dispersible in water also. The joint use of the combination of the cellulosic compound and polyvinyl alcohol is particularly elfective for soil-suspension properties during the washing of a variety of fabrics, including both cotton and synthetic fibers such as nylon, Dacron and resin-treated cottons. The mixture is used preferably in a total amount of 0.1 to 2 percent by weight of the solids. Preferred cellulosic compounds are the alkali metal salts of a carboxy lower alkyl cellulose having up to 3 carbons in the alkyl group, such as the sodium and potassium salt of carboxymethylcellulose. Suitable salts are sodium carboxyethylcellulose; the cellulose sulfates and lower alkyl and hydroxyalkylcellulose ethers such as methyl-, ethyl-, and hydroxyethylcellulose.

The compositions described herein are particularly and advantageously adapted for use in connection with the bleaching and washing of stained and/or soiled fibrous products, the latter including fabrics, garments, household laundry and the like. In actual use, the stabilized composition is dissolved in aqueous media whereby to achieve uniform dispersion of the involved ingredients. The aqueous solution thus obtained may be then contacted with the material to be bleached. The provision of the bleaching composition in aqueous form alfords the advantage that any possibility of uneven or localized bleaching and possibily fiber damage is minimized, if not avoided, whereas the use of the bleaching composition in dry form presents significant risk of injury to the fabric under treatment. Thus, elfectuation of oxidative bleaching and washing in accordance with the present invention preferably comprises commingling the stabilized N-chloro composition with water in amounts consonant with efiicacious bleaching action and thereafter contactlng the resulting aqueous mixture with the material to be bleached. Moreover, optimum bleaching action obtains in those instances wherein the bleaching treatment is carried out within a short time following formulation of the aqueous bleaching solution, e.g., within about 3 minutes thereafter. Alternatively, the oxidative treatment prescribed by the present invention may also be accomplished by first immersing the textile in an aqueous medium and thereafter introducing the composition comprising the mercaptan stabilizer and N-chloro-irnide bleaching agent.

It will be understood, of course, that the concentration of bleaching composition employed may be varied within relatively wide limits depending upon the nature of the oxidation problem encountered. Thus, rather concentrated solutions are permitted when treating stained ceramics since the possibility of damage to the ceramic material is highly remote. In such instances, the bleaching composition may be applied as such to the selected surface to be treated and thereafter adding Water in amounts sufiicient to form a paste or slurry of the desired consistency. As will be recognized in such procedures, formation of the aqueous bleaching medium occurs in the presence of the material to be treated.

The following examples are given for purposes of illustration only and are not to be considered as necessarily constituting a limitation of the present invention.

A series of cleanser compositions having the following compositions is prepared.

l A composition consisting of, by weight: 60% linear alkylbenzene sulfouate, sodium; 10% sodium silicate; 014% Iphol (mixture of orthoeresol. isopropyl alcohol, 113104 and soda ash); 2.0% water; balance sodium sulfate.

The isobornyl acetate is not in itself a stabilizer but is added to expedite uniform and homogeneous dispersion of the involved ingredients and particularly the octyl mercaptan. In order to determine the stability of the above identified compositions against loss of chlorine upon standing each of such compositions are subjected to aging treatment employing a tempearture of 140 F. Measurements to determine chlorine content are taken at the intervals specified in the following table. The results are as follows:

TABLE 1 Stability at 140 F.

Percent available chlorine Days 6 9 Example No.2

Determination of available chlorine content is determined via two thiosulphate titrations which are effected by first storing the sample minutes in water before addition of potassium iodide or sulfuric acid. This method of determining the available chlorine content is somewhat more reliable since trichlorocyanuric acid (TCCA) exhibits a tendency to degrade to a form comprising ineffective bleaching species. However, normal thiosulphate titration will in most instances indicate stability of the trichloroisocyanuric acid despite such degradation. However, the titration method employed in these instances reflects quantatively only that proportion of trichloroisocyanuric acid which has not undergone decomposition.

As the data in the above table makes manifestly clear, the presence of the mercaptan stabilizer imparts to the composition an exceptional level of chlorine stability, this observation being confirmed according to both of the chlorine determination methods employed. Of primary importance is the fact that the improved chlorine stabilization result obtains despite subjection of the test compositions to rather severe temperatures, i.e., on the order of 140 F. Accordingly, the significance of the accumulated data becomes all the more apparent. As will be observed, after 3 days, the chlorine loss of the stabilized composition approximated 9%. However, it is significant to note that the available chlorine level of 0.38 remained substantially constant thereafter. In contradistinction, each of the cleanser compositions prepared omitting the mercaptan stabilizer exhibits an intolerable loss of available chlorine after a period of only 3 days. In addition, the available chlorine level continues to diminish markedly with increased periods of standing,

EXAMPLES 4-6 Examples 1 to 3 are repeated except that in each case, 2.7% by weight of sodium sulfate decahydrate (Na SO -10H O) is added to the respective compositions, the addition being made for purposes of enabling stability evaluations in the presence of significant quantitles of moisture. Thus, under the conditions employed in the testing, the bound water content of the sodium sulfate is released. The results obtained are itemized in the following table: (Examples 4, 5 and 6 correspond respectively to Examples 1, 2 and 3).

TABLE 2 Stability at F.

Percent available chlorine 15 Negligible Negligible l6 Negligible Negligible 37 37 36 EXAMPLES 7-8 Example 3 is repeated except that the stabilizer compound employed comprises dodecyl mercaptan and benzyl mercaptan respectively. The results obtained are itemized in the following table:

TABLE 3 Stability at 140 F.

Percent available chlorine Days 0 3 6 9 Stabilizer Example No.:

7 .45 .24 .24 .23 Dodecyl mercaptan. 8 .43 .36 .36 .35 Benzyl mercaptan.

Titration experiments to determine percent chlorine content are conducted according to the procedure described in connection with Example 1. Again, the results obtained clearly indicate the superior stabilizing action of the mercaptan compounds. The results obtained for the dodecyl mercaptan compound, although somewhat lower by comparison to the benzyl mercaptan species, nevertheless establish rather marked improvement over a control sample for which negligible chlorine content was indicated after 6 days standing. The com ositions of Examples 7 and 8 exhibited similar improvement when tested in the presence of moisture, i.e., sodium sulfate decahydrate in the manner described in connection with Examples 4-6.

In practical terms, the implications suggested by the above data cannot be overemphasized. As explained hereinbefore, it is of critical importance to the efficacy of a given bleach composition that exceptional stability against chlorine loss be obtainable despite extended periods of storage under varying conditions of temperature, humidity, etc. Thus, it is inevitable that the cleanser composition during periods of transport, storage, and/ or use, will be subjected to conditions conducive to moisture pickup. This situation obtains despite the precautionary matters observed as regards packaging, handling, etc. Thus, one of the particularly beneficial advantages made possible by the present invention becomes clearly evident, namely, the exceptional stability against chlorine loss despite the presence of moisture. Improved stability against chlorine loss presents manifold advantages from an economical standpoint. Thus, the effectiveness of bleach compositions being critically dependent upon available chlorine content becomes seriously impaired when stored for even moderately extended periods of time under relatively mild conditions of temperature and humidity in the absence of effective stabilizing agents. In order to compensate for the net loss in available chlorine content, it becomes necessary in practice to resort to the use of increased proportions of bleach compositions. In view of the lower volume efliciency characterizing the non-stabilized cleanser materials, the added cost increment necessarily attending the use of such materials may be prohibitive.

Results similar to those described in the foregoing examples are obtained when the procedures described therein are repeated but employing in lieu of triachloro isocyanuric acid (TCCA), one or more of dichloroisocyanuric acid, sodium dichloroisocyanurate and potassium dichloroisocyanurate. In each instance, superior stabilization against chlorine loss is obtained despite the use of the mercaptan compound in minimal concentrations, i.e., concentrations falling within the range of 0.001% to 0.1% by weight of total composition. It should be emphasized that the concentration of mercaptan employed is critical solely from the standpoint that it be present in amounts sufficient to stabilize against loss of chlorine. Apart from this particular requirement, concentration selection may vary within relatively wide limits. Moreover, unusually excessive quantities, i.e., on the order of by weight of composition should be avoided in order to minimize any possibility of deleteriously affecting the N-chloro-imide compound. Improved stabilization against chlorine loss likewise obtains in the foregoing examples when the mercaptan compound selected for use comprises n-butyl mercaptan, isobutyl mercaptan, n-hexyl mercaptan, n-pentyl mercaptan, sec-pentyl mercaptan, and n-decyl mercaptan, with the improvements noted being particularly evident in connection with compositions containing alkali metal salts of dichloroisocyanuric acid; however, significant improvement in chlorine stabilization over control samples typified mercaptan-stabilized, trichloroisocyanuric acid and dichloriosocyanuric acidcontaining compositions.

The composition contemplated by the present invention may comprise simply a mixture of the N-chloro-irnide compound and mercaptan stabilizer, the latter being employed within the mole ratio range hereinbefore specified. Thus, highly useful bleaching, disinfecting, etc., compositions may be so formulated. The superior stabilizing function of the mercaptan compound is particularly manifest in such compositions, evaluative testing in connection therewith in the manner herein exemplified indicating chlorine losses of 10-12% and less after 69 days standing at temperatures of 140 F.

The present invention has been described with respect to certain preferred embodiments thereof and there will become obvious to persons skilled in the art other variations, modifications and equivalents which are to be understood as coming within the scope of the present invention.

What is claimed is:

1. A cleansing composition stabilized against loss of chlorine consisting essentially of (a) an N-chloroimide bleaching agent selected from the group consisting of dichloroisocyanurio acid, trichloroisocyanuric acid, alkali metal salts thereof, and (b) a mercaptan compound of the following structural formula:

wherein R is selected from the group consisting of alkyl containing from 4-12 carbon atoms, phenyl and benzyl, said mercaptan being present in amounts suflicient to stabilize said N-chloroimide against loss of chlorine.

2. A composition according to claim 1 wherein said N- chloroimide is trichloroisocyanuric acid.

3. A composition according to claim 1 wherein said N- chloroimide is dichloroisocyanuric acid.

4. A composition according to claim 1 wherein said N- chloroimide is sodium dichloroisocyanurate.

5. A composition according to claim 1 wherein said N- chloroimide is potassium dichloroisocyan-urate.

6. A composition according to claim 1 wherein said mercaptan compound is octyl mercaptan.

7. A composition according to claim 1 wherein said mercaptan compound is dodecyl mercaptan.

8. A composition according to claim 1 wherein said mercaptan compound is benzyl mercaptan.

9. A composition according to claim 1 wherein said mercaptan compound is isobutyl mercaptan.

10. A composition according to claim 1 wherein said mercaptan compound is isobutyl mercaptan.

11. A composition according to claim 1 wherein said mercaptan compound is n-pentyl mercaptan.

12. A composition as defined in claim 1 wherein the mole ratio of mercaptan compound to N-chloro-imide bleaching agent ranges from 1/1 to 1/20.

References Cited UNITED STATES PATENTS 3,278,443 10/1966 Bright et al. 252102X MAYER WEINBLATT, Primary Examiner US. Cl. X.R. 

